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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2013-01-29 17:45:49 -0500
committerSteven Rostedt <rostedt@goodmis.org>2013-01-30 11:01:53 -0500
commitad964704ba9326d027fc10fd0099b7c880e50172 (patch)
treee08884c0f383e5b954233c323df67a3d726b6537 /kernel
parent03274a3ffb449632970fdd35da72ea41cf8474da (diff)
downloadop-kernel-dev-ad964704ba9326d027fc10fd0099b7c880e50172.zip
op-kernel-dev-ad964704ba9326d027fc10fd0099b7c880e50172.tar.gz
ring-buffer: Add stats field for amount read from trace ring buffer
Add a stat about the number of events read from the ring buffer: # cat /debug/tracing/per_cpu/cpu0/stats entries: 39869 overrun: 870512 commit overrun: 0 bytes: 1449912 oldest event ts: 6561.368690 now ts: 6565.246426 dropped events: 0 read events: 112 <-- Added Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ring_buffer.c18
-rw-r--r--kernel/trace/trace.c3
2 files changed, 21 insertions, 0 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 13950d9..7244acd 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3103,6 +3103,24 @@ ring_buffer_dropped_events_cpu(struct ring_buffer *buffer, int cpu)
EXPORT_SYMBOL_GPL(ring_buffer_dropped_events_cpu);
/**
+ * ring_buffer_read_events_cpu - get the number of events successfully read
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the number of events read
+ */
+unsigned long
+ring_buffer_read_events_cpu(struct ring_buffer *buffer, int cpu)
+{
+ struct ring_buffer_per_cpu *cpu_buffer;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return 0;
+
+ cpu_buffer = buffer->buffers[cpu];
+ return cpu_buffer->read;
+}
+EXPORT_SYMBOL_GPL(ring_buffer_read_events_cpu);
+
+/**
* ring_buffer_entries - get the number of entries in a buffer
* @buffer: The ring buffer
*
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index d399592..90a1c71 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4430,6 +4430,9 @@ tracing_stats_read(struct file *filp, char __user *ubuf,
cnt = ring_buffer_dropped_events_cpu(tr->buffer, cpu);
trace_seq_printf(s, "dropped events: %ld\n", cnt);
+ cnt = ring_buffer_read_events_cpu(tr->buffer, cpu);
+ trace_seq_printf(s, "read events: %ld\n", cnt);
+
count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
kfree(s);
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